1. Field of the Invention
The present invention relates to a conductor used as fuse which functions to instantaneously open a related circuit when an overcurrent exceeding a rated current flows, and particularly to a conductor to be used as fuse which is incorporated in a semiconductor device such as an IC or a transistor, or in a circuit component such as a capacitor. The present fuse conductor functions to prevent burning of the device or the component by opening the circuit of the device or the component when an overcurrent flows therein or when it is overheated.
2. Background Information
Conventionally, a metal such as Pb or Zn, or a Pb-Sn alloy is normally used as a fuse as mentioned in "Metal Manual (fourth edition issued Dec. 20, 1982, p. 1007)" edited by the Japan Institute of Metals. The fuse conductor formed of such metal or alloy is melted by Joule heat caused by an overcurrent, thereby to open an electric circuit. If it is desired to accurately set a "fusing" current independently of an outside air temperature, a conductor for a fuse formed of a tungsten wire is sometimes used. A Wood's metal melting at a low temperature is utilized as a fuse of a type melting by overheat in a heating atmosphere.
However, if it is desired to use any of such fuse conductors to add a circuit breaker function to a semiconductor device or a circuit component, it is difficult to draw the conductor to a fine wire or an extra fine wire which can be used. Consequently, under such circumstances, another device having a circuit breaker function is incorporated in a circuit of an electronic apparatus including. If such a fuse conductor itself is directly used, it is used in the form of a plate or a thick wire provided with notches for example so that its cross-sectional area is decreased.
Although a fine wire or an extra fine wire of Al, an alloy of Al, Cu or an alloy of Cu may be used as a fuse conductor, such a fuse conductor is not readily melted by an overcurrent.